Conventionally, a portable electric power tool such as an electric drill or an impact driver is held by a user's belt using a locking member such as a hook or the like fastened to the belt as disclosed in Japanese Patent Application Publication Nos. 2004-255503 and 2005-313322, in which state the user moves to a job site or conducts preparations for works, e.g., a task of mounting a workpiece to which a rotational drive force is outputted.
For example, Japanese Patent Application Publication No. 2004-255503 discloses an electric power tool including a grip part, a drive part (body part) respectively provided at the upper side of the grip part and a base part having a battery chamber (battery). A leg portion of a hook for use with a belt is attached to the side wall of the base part. The hook is inserted between the belt and the waist so that the belt can be positioned between the hook and the base part. Thus, the electric power tool is held by the belt in a posture inverted to the in-use posture, namely in such a posture that the axis of the grip part extends in a vertical direction with the front end of the drive part facing toward the user's back.
Japanese Patent Application Publication No. 2005-313322 discloses an electric power tool including a body part for accommodating a motor and a handle part (grip part) suspended from the body part. A hook-shaped locking member is removably attached to the side surface of a lower end portion of the handle part. The electric power tool is held by a belt in such a way that the locking member is inserted and interposed between the belt and the waist. In particular, the locking member is rotatable with respect to the side surface of the lower end portion of the handle part. This makes it possible to change the posture of the electric power tool held by the belt. By allowing the grip part to extend horizontally along the belt, it is possible to hold the electric power tool in a posture in which there is no need to twist the wrist of the hand holding the grip part.
With the electric power tool held by the belt in an inverted posture as disclosed in Japanese Patent Application Publication No. 2004-255503, there is a need to heavily twist the wrist of the hand gripping the grip part when detaching the tool from the belt. This imparts a heavy burden on the wrist during detachment of the tool, thereby making it inconvenient to use the tool. In case of the electric power tool whose posture can be changed in the belt-held state as disclosed in Japanese Patent Application Publication No. 2005-313322, the wrist bears a reduced burden. However, if the user has a corpulent body, the abdominal fat leaves no gap between the grip part and the belt, which makes it impossible to insert the thumb between the grip part and the belt. In addition, the upper portions of the locking member and the belt are hidden under the abdomen, which makes it difficult to remove the locking member from the belt. Moreover, if the thumb is inserted by force or if the tool is forcibly removed from the belt, the locking member may be separated from the tool or may be deformed. This may be a cause of failure or breakage.
In other words, since the locking member is directly fastened to the belt in the conventional electric power tools, the abdomen may become an obstacle depending on the body type of a user. This poses a problem in that it becomes difficult to attach and detach the electric power tool. Furthermore, since the electric power tool is virtually fixed to the belt in the belt-held state, the tool may make contact with the user's leg and may sometimes drop from the belt. This may restrain movement of the user who performs work preparations with the electric power tool held by the belt.
Additionally, since the locking member is arranged below the grip part, it is hidden under the hand or the arm gripping the grip part when fastening the locking member to the belt. Thus, the user cannot know where the tip end portion of the locking member exists. This poses a problem in that it is difficult to attach the locking member to the belt.